Comment 37 for bug 124581

It's happening again for me right now, so I'm investigating more;

The greyed out characteristic affects just one window in Firefox; if I open a link in another window that is in normal colour. Opening the link in another tab in the greyed out window stays monochrome.

Staying in the monochrome window, all the dropdown menus display in colour. That includes bookmarks, feed bookmarks, smart bookmarks, address bar, google bar, and menu bar items (File, Edit etc.)

Changing the System=>Preferences=>Appearance=>Visual Effects from 'Normal' to 'Extra' instantly restored the window to colour.

Possible trigger for the symptom is heavy activity in Evolution alongside Firefox.

So two workarounds present themselves; reopen everything in a new window and close the old one, or just tweak the Visual Effects settings to a different level.

Will now try to see if I can provoke the symptom by running intensive Evolution activities alongside Firefox.

Neil